1. Technical Field
The present invention relates to a liquid crystal display (LCD), and more particularly to an active matrix liquid crystal display (AMLCD).
2. Discussion of Related Art
An LCD controls the erect or alignment state of the liquid crystal molecules of each pixel by driving corresponding thin film transistors (TFTs). The LCD has a plurality of pixels aligned in a predetermined direction. The TFTs operate by driving signals supplied to gate electrodes through gate lines. The gate lines pass through the pixels aligned in the predetermined direction. Each pixel has a liquid crystal capacitor and one terminal of the liquid crystal capacitor is connected to one terminal of the TFT. Sub-capacitor lines extend in parallel to the gate lines over a plurality of pixels. The sub-capacitor lines transmit signals to sub-capacitor devices. A sub-capacitor device is connected between the sub-capacitor line and one terminal of each TFT. A driving circuit is connected to the sub-capacitor lines and applies a voltage to the sub-capacitor lines. As the voltage is applied to the sub-capacitor lines through the driving circuit, the sub-capacitor devices are charged and the sub-capacitor devices are capacitively coupled to the liquid crystal capacitors. As a result, the erect state or alignment state of the liquid crystal molecules in each pixel is maintained.
The liquid crystal molecules may be fixed at a desired erect or alignment state by applying voltages having two different values to the sub-capacitor lines. However, adjusting the erect or alignment state of the liquid crystal molecules to a desired state by using the two different voltage values can be difficult. Further, the liquid crystal molecules may take a relatively long time in transitioning to the erect or alignment state and it can be difficult to improve the response speed of the liquid crystal molecules.
Thus, there is a need for an LCD that can rapidly adjust the alignment of liquid crystal molecules into a desired erect state.